December 22 to 24, 2007
Most big snowstorms that occur in Duluth are terrain enhanced or lake enhanced at some point in time during the event. Strong east component winds (east-southeast to east-northeast) funneling into the head of the lake or into the higher elevations along the north shore of Lake Superior contribute to the aforementioned enhancements. Strong northwest to north winds gusting 35 to 40 mph prevailed through the storm at hand so these enhancements were not a factor for Duluth. We got snow the old fashion way this time; a big, strong, wound up, bombing out, Gulf of Mexico juiced-up storm that dumped loads of snow at rates of one inches or more per hour.
An upper level low pressure wave ejected north from a larger trough over the Southern Plains. A rain and snow mixture began around 5:30 AM Saturday morning December 22nd. The precipitation changed to all snow within two hours along and inland of the ridge crest but remained mostly rain though the event at the bottom of the hill. The snow decreased to flurries by 12 noon. Slushy snow accumulated 1.7 inches at this observer's location and 2.5 inches at the National Weather Service. A few flakes or snow grains persisted through the afternoon into the evening.
As the upper level trough over the southern plains moved northeast, it merged with another upper level low pressure system moving south from Canada. A surface low pressure system rapidly intensified in eastern Wisconsin Sunday morning. The low moved north across the Upper Peninsula of Michigan to central Lake Superior during the afternoon and evening.
Very light snow began to move north into Duluth from the south toward 10 PM Saturday evening and at the same time started to develop overhead. Widespread light snow wrapped west into the area overnight but snow and wind gradually increased in intensity by 4 AM. From 6 AM through the morning moderate to heavy snow accumulated an inch or more per hour with the wind continuing to get stronger. Full blown snowstorm in progress! The snow let up a bit at 1:30 PM but still continued to fall at an occasionally moderate rate for the rest of the afternoon. Snow decreased to flurries around 7:30 PM and continued intermittently overnight into the early daylight morning Monday December 24th.
This second shot of snow produced an additional 9.3 inches at this observer's location. The national Weather service reported 10.4 inches.
National Weather Service 12.9 inches
My total 11.0 inches
Storm images compliments of the National Weather Service and the National Centers for Environmental Information
WSR-88D Radar Image 7:19 AM CST 12/23/2007
Infrared Satellite Image 5:15 AM CST 12/23/2007
12 noon CST December 23, 2007